The present invention relates to novel N-substituted tetrahydrophthalimides and herbicidal compositions thereof.
N-substituted aryl-.DELTA.'-tetrahydrophthalimide derivatives having herbicidal activity have been reported.
For example, Japanese Examined Patent Publication No. 11940/1973 (U.S. Pat. No. 3,878,224 and U.S. Pat. No. 3,984,435 and West German Unexamined Patent Publication 2,165,651) discloses N-substituted-.DELTA.'-tetrahydrophthalimide which is represented by the general formula ##STR1## wherein R may be an aryl or aralkyl as phenyl optionally substituted with 1 to 5 halogen atoms; hydroxy, alkoxy, nitro, cyano, thiocyanno, carboxy, halogenated alkyl, alkyl, phenyl and OCH.sub.2 A (wherein A is phenyl or naphthyl) group and the like may also be substituted therein. N-(4-chloro-3-methoxyphenyl)-.DELTA.'-tetrahydrophthalimide and N-(4-bromo-3-methoxyphenyl)-.DELTA.'-tetrahydrophthalimide are described as the exemplified compounds having the formula wherein R is a halogen- and alkoxy-substituted phenyl group.
U.S. Pat. No. 4,001,272 and U.S. Pat. No. 4,032,326 disclose herbicidal 2-substituted aryl-4,5,6,7-tetrahydro-2H-isoindole-1,3-diones of the following formula: ##STR2## wherein X is Cl, Br or F and Y is H or F.
The activity of these compounds is very substantially affected by the type of substituents encompassed by the above generic formula, the number of these substituents and the structural positions of the substituents. Thus, it is difficult to predict herbicidal effects of novel compounds in view of similarity of chemical structures.
The inventors have studied novel tetrahydrophthalimides as an active ingredient of a herbicidal composition and have found that the specific novel N-aryl-3,4,5,6-tetrahydrophthalimides having H or a halogen atom at 2-position, a halogen atom at 4-position and a specific substituent at 5-position have excellent herbicidal effect.